Minigun Supergun - An Open Source Supergun

[Raph_friend]

You're not missing anything.

I've only done a schematic for the video circuit and that's more of a visual reference rather than a means to route the PCB.

I whipped the PCB up sans schematic, I trust myself more than I trust software.

I see, very impressive working without a schematic!
I wanted to take a look at the audio circuits. I think one of the audio channels is polarity inverted -- at least when the minigun is in mono audio mode. I suspect this because my audio is routed through a surround sound receiver. If the receiver is in Dolby Pro Logic mode, I would expect the audio to to routed 100% to the front center channel. But instead the audio is routed 100% to the rear channel. That tells me the left and right channels are 180 degrees out of phase.

This happens with audio through the mini din port. I have not tested the 1/8 inch audio port yet. Nor have I tested with a stereo JAMMA PCB. I also have not eliminated the possibility that my Retro access SCART cable is inverting one of the audio channels -- this is the first time I've used it in anger.

I would like to ask about the audio circuitry too, but I do not like to be annoying, I had already asked for the video.

 

[Frank_fjs]

You're aware that to utilise stereo audio the game board must be capable of outputting stereo audio over the jamma edge?

This really only applies to certain MVS boards that have this ability and they will have a switch themselves to alternate between mono and stereo output. The Minigun needs to be matched to this setting, so mono selected on the MVS and mono selected on the Minigun, or stereo selected on the MVS and Minigun.

If you're outputting mono from the game board but have the Minigun set to stereo then the audio will be out of phase.

 

[the Goat]

If you're outputting mono from the game board but have the Minigun set to stereo then the audio will be out of phase.

I am embarrassed to admit I had the stereo/mono switch in the wrong position. I was certain I had it in mono mode. But when I checked it this morning it was in stereo mode. The out of phase audio was my own fault. Sorry.

 

[pacoarcade]

I confirm the high pitched noise using the RT-125A happens with MV1B, MV1C and even MV1FZS (not so audible). It's due to low current draw from the arcade board and it has nothing to do with the Minigun.

I currently use the 42PP0606 (MWP-606) with these boards, this one apparently works fine, no annoying noise or problems so far.

 

[AlxUnderBase]

I confirm the high pitched noise using the RT-125A happens with MV1B, MV1C and even MV1FZS (not so audible). It's due to low current draw from the arcade board and it has nothing to do with the Minigun.

I currently use the 42PP0606 (MWP-606) with these boards, this one apparently works fine, no annoying noise or problems so far.

it's time to buy another source then since the rt-125A will produce noice with MV1C systems... or it's something we can do about that noise won't happened with MV1C using that RT-125A source?

 

[pacoarcade]

You can put a parallel load in +5V line with a cement resistor calculating the value to draw ~1.5-2A and using a good wattage margin, anyway I think the 42PP0606 is better.

The RT-125A produces a wavy noise in some games, I've read that connecting FG and COM fixes the issue but I'm not sure if this is advisable (seen here). With the 42PP0606 I've not experienced this problem, and there is continuity between these terminals.

Also, the 42PP0606 has less ripple (50mVpp vs 80mVpp) and features soft start. If I recall correctly, the RT-125A doesn't have a thermistor to limit inrush current.

I've resoldered the voltage adjustment pot since I've read about its tendency to crack, so if you get this PSU take this into account. Some units come with Jamicon and CapXon capacitors, I've replaced them with japanese Panasonic and Rubycon of similar characteristics (if you are interested I can post the replacement capacitors). In my RT-125A, except one little jamicon all the electrolytic capacitors are Rubycon.

 

[AlxUnderBase]

You can put a parallel load with a cement resistor calculating the value to draw ~1.5-2A and using a good wattage margin, anyway I think the 42PP0606 is better.

The RT-125A produces a wavy noise in some games, I've read that connecting FG and COM fixes the issue but I'm not sure if this is advisable (seen here). With the 42PP0606 I've not experienced this problem, and there is continuity between these terminals.

Also, the 42PP0606 has less ripple (50mVpp vs 80mVpp) and features soft start. If I recall correctly, the RT-125A doesn't have a thermistor to limit inrush current.

I've resoldered the voltage adjustment pot since I've read about its tendency to crack, so if you get this PSU take this into account. Some units come with Jamicon and CapXon capacitors, I've replaced them with japanese Panasonic and Rubycon of similar characteristics (if you are interested I can post the replacement capacitors). In my RT-125A, except one little jamicon all the electrolytic capacitors are Rubycon.

I'm interested to replace all caps as well . i will place a new order on digikey in few days and will be fine to grab new caps . if this fix will be safe,i don't mind to connect a cable between those gnd & com leads. thank you sir for your detalied reply. you resolder the pot on Rt-125A ? or in 42PP0606?

 

[pacoarcade]

42PP0606. I don't know if the RT-125A has the same problem. Here you can find more information about the recap I did: https://www.badcaps.net/forum/showthread.php?p=885680.

If the caps from the RT-125A are Rubycon I wouldn't replace them, it's a top quality brand along with Panasonic (Matsushita), Chemi-con and Nichicon.

Please take into account that manipulating a PSU can be lethal (even with the power supply unplugged) due to the charge of the big capacitors.

 

[AlxUnderBase]

grabbed yesterday v1.7 revision ... the parts are on the way too. . i can't wait to solder smd parts on this

 

[Frank_fjs]

Great!

Share some pics when finished please.

 

[AlxUnderBase]

Great!

Share some pics when finished please.

For sure sir ! Depends on how to be my US orders (i purchased some goodies from US who must be shipped in RO,the parts are on my US address) will be boxed and shipped to Romania

 

[XeD]

You can put a parallel load in +5V line with a cement resistor calculating the value to draw ~1.5-2A and using a good wattage margin, anyway I think the 42PP0606 is better.

The RT-125A produces a wavy noise in some games, I've read that connecting FG and COM fixes the issue but I'm not sure if this is advisable (seen here). With the 42PP0606 I've not experienced this problem, and there is continuity between these terminals.

Also, the 42PP0606 has less ripple (50mVpp vs 80mVpp) and features soft start. If I recall correctly, the RT-125A doesn't have a thermistor to limit inrush current.

I've resoldered the voltage adjustment pot since I've read about its tendency to crack, so if you get this PSU take this into account. Some units come with Jamicon and CapXon capacitors, I've replaced them with japanese Panasonic and Rubycon of similar characteristics (if you are interested I can post the replacement capacitors). In my RT-125A, except one little jamicon all the electrolytic capacitors are Rubycon.

I feel good ordering some mwp606 for this project and future one. Thanks for the detail

 

[arcadeqc]

I assembled a v1.5 advanced Minigun this week while I wait for some v1.7 boards to arrive. I'm missing some cables to hook it up and test it, which I'm currently working on.

I also have some v1.2 and v1.4 advanced PCBs, cause I'm trigger happy like that, that I will not be using. If anyone wants one of these, DM me, and I can arrange to mail it out to you in a simple envelope for cheap. I'm in Canada, and I'm building a couple of v1.7 advanced Miniguns for myself and a couple of friends, also DM if you're interested.

 

[ebzero89]

Hey there! Just ordered up a few rev 1.7 advanced PCBs and was wondering if there's any particular reason I couldn't make an adapter from the 8pin DIN to a VGA out put. Would there be any trouble running this to an LCD monitor provided the pinout is correct? I have also ordered an OSSC for different reasons, but would be able to use it here if there's something I don't know about that would cause issues with going directly from this board to an LCD via VGA.

 

[the Goat]

Hey there! Just ordered up a few rev 1.7 advanced PCBs and was wondering if there's any particular reason I couldn't make an adapter from the 8pin DIN to a VGA out put. Would there be any trouble running this to an LCD monitor provided the pinout is correct? I have also ordered an OSSC for different reasons, but would be able to use it here if there's something I don't know about that would cause issues with going directly from this board to an LCD via VGA.

VGA needs separate hsync & vsync. The minigun only outputs combined csync. So a passive 8pin mini din to VGA adapter won't be possible.

 

[ebzero89]

VGA needs separate hsync & vsync. The minigun only outputs combined csync. So a passive 8pin mini din to VGA adapter won't be possible.

So then I'll need to go to the OSSC then?

 

[the Goat]

VGA needs separate hsync & vsync. The minigun only outputs combined csync. So a passive 8pin mini din to VGA adapter won't be possible.

So then I'll need to go to the OSSC then?

An Extron 201 RXi will convert the RGBS from the minigun to VGA. I don't know if the OSSC can do that.

 

[Raph_friend]

VGA needs separate hsync & vsync. The minigun only outputs combined csync. So a passive 8pin mini din to VGA adapter won't be possible.

So then I'll need to go to the OSSC then?

An Extron 201 RXi will convert the RGBS from the minigun to VGA. I don't know if the OSSC can do that.

Extron RGB will only get the combinated sync Csync and process, and may be possible to ouput H/V, but some PCB still need sync strike (LM1881, LMH1980, etc) and some will get problems (up screen distortion). I think RGB's Supergun can ouput H/V but i really don't know what video curcuit he's using.

 

[ebzero89]

VGA needs separate hsync & vsync. The minigun only outputs combined csync. So a passive 8pin mini din to VGA adapter won't be possible.

So then I'll need to go to the OSSC then?

An Extron 201 RXi will convert the RGBS from the minigun to VGA. I don't know if the OSSC can do that.

Extron RGB will only get the combinated sync Csync and process, and may be possible to ouput H/V, but some PCB still need sync strike (LM1881, LMH1980, etc) and some will get problems (up screen distortion). I think RGB's Supergun can ouput H/V but i really don't know what video curcuit he's using.

It doesn't much matter, I'm fine as long as the OSSC can take csync input, which it appears to do. I'll be going to an LCD for the time being, so HDMI is available as an input option. I just need to make sure that this board will attenuate the video properly so as to not fry it. As for going to VGA directly, I think earlier in the thread someone mentioned a "test bench" version of the PCB that had VGA out directly, so I guess the H/V lines are available somehow.

 

[Frank_fjs]

In the case of the OSSC, it accepts a composite sync signal via the VGA input (pin 13). Other monitors have this capability too but it's all down to the monitor in question. So yes, you could fabricate a mini DIN to VGA adapter and run the Minigun to the OSSCs VGA input. There's no compelling reason to do so however, outside of Taito F3 but unless you modify the Minigun to output TTL level sync there's no point.

As is, the Minigun is safe to use with an OSSC.